1. Field of the Invention
The present invention relates generally to roller members, and more particularly to an improved roller member for use in an upwardly-acting door structure.
2. Description of the Prior Art
Rollers and roller members are used in many different applications. For example, such rollers are used to guide movement of an upwardly-acting door structure along a track. Variations of such rollers are also utilized in roller conveyors.
The design of such roller members depends largely upon the service loading encountered. For example, the rollers in a roller conveyor are designed to withstand radial loads, but are not expected to encounter substantial thrust loads. On the other hand, some upwardly-acting doors, such as the roll-up door on the back of a truck, may have to be designed to resist thrust as well as radial loads.
Examples of prior art rollers and roller members may be found in one or more of the following U.S. Pat. Nos.: 3,416,589; 4,017,128; 4,120,543; 4,145,093; 3,994,544; 3,885,840; 3,230,022; and 887,265.